Secondary outcome will be accuracy (no. of errors) and timing (speed) variability of force adaptation in the visuomotor task (Celnik, own data), and pinch force at all other time points, including day 5 as a measure of learning over the training period and 3 months as a measure for long-term retention. In the patient group the Jebsen Taylor Test will be used to assess gross motor function. To better understand the mechanisms underlying the proposed behavioral gains, we will use single- and paired pulse transcranial magnetic stimulation (TMS) to identify corticomotor excitability changes. Furthermore the volunteers will answer several questionnaires to evaluate fatigue and mood (PANAS) and perform short neuropsychological control task to control for changes in attention and memory function.